Letters from Count Algarotti to Lord Hervey and the Marquis Scipio Maffei : containing the state of the trade, marine, revenues, and forces of the Russian empire : with the history of the late war between the Russians and the Turks, and observations on the Baltic and the Caspian seas : to which is added, a dissertation on the reigns of the seven kings of Rome, and a dissertation on the empire of the Incas